Social search engine Posse, the brainchild of Wellington woman Rebekah Campbell, is about to enter the United States market and launch a mobile app after $3.5 million of investment.

The website, founded in 2011, acts as a verified recommendation service. Users sign in with Facebook, Twitter or email then create virtual themed streets (My favourite Wellington coffee shops, Best baguettes in Paris) populated with their favourite businesses.

"It is all about status, showing that you discovered all these great things. You want to show you like all the best places on there because it makes you look cool, like you discovered all these great bars," said Campbell, who worked as a music manager for a decade before starting the website.

Business owners are notified of their popularity on the site and given access to information about customers recommending them. By paying Posse a monthly fee, its only revenue stream aside from sponsored content, retailers can send offers directly to customers who promote them.

Around 70 per cent of users were adding more than 4 places to their "streets" and 42 per cent remained active on a weekly basis after three months.

"That's really good engagement."

Some retailers gave gifts to people who nominated them and although Campbell said people felt "dirty" about recommending businesses to get rewards, they were excited when given something for free as a surprise. "It is genuinely a reward system, a thanking system - not a loyalty programme way but of building a relationship with customers."

The design appealed to the female market.

On competing location-based social networking website FourSquare, 70 per cent of users were male. That website had a game-like format of checking in at businesses to become "mayor" of a place which she said was "like marking territory".

However women liked creating and cultivating online profiles as well as collecting and displaying favourite things, such as on the popular pin-board style website Pinterest.

Now based in Sydney, former Wellington Girls' student Campbell hit headlines in 1998 by creating the Life Festival at age 20, raising $40,000 to organise musicians such as Tim Finn to play a concert to 15,000 people to raise awareness of youth suicide.

The same celebrity star power and fundraising nous has been applied to Posse. It has Google Maps co-founder Lars Rasmussen and Twitter investor Bill Tai on its board, and Campbell raised the balance of the $3.5m cost of Posse so far after putting in around $130,000 of her own money.

Posse will have its official launch in to the US market in March. Campbell is hiring two staff to head up its New York City office, and is also looking for a Wellington based part-timer. So far, it had 25,000 users but was aiming for a quarter of a million by Christmas. "I think the business will be profitable by the end of the year, that's our aim."